1. Field of the Invention
The present invention relates to a spacer inserted in a gap between an existing pipe and a rehabilitating pipe to adjust the position of the rehabilitating pipe, and a method for adjusting the position of a rehabilitating pipe using such a spacer.
2. Description of the Prior Art
A method for rehabilitating an existing pipe such a sewer pipe is known in which a rehabilitating pipe is laid inside the existing pipe and a compound pipe is constructed by filling the gap between the outer periphery of the rehabilitating pipe and the inner wall surface of the existing pipe with a filler and then hardening the filler. This existing pipe rehabilitating work normally requires the fixing of the rehabilitating pipe by adjusting the position of the rehabilitating pipe in the upper, lower, left, and right directions inside the existing pipe to a position slightly offset downward from the position concentric with the existing pipe so that the lower end of the outer periphery thereof contacts the bottom of the existing pipe.
The purpose of this is to ensure the flow of fluid inside the existing pipe by lowering the bottom of the rehabilitating pipe so that it approaches the bottom of the existing pipe as much as possible, and to thicken and strengthen the filler on the upper side because the majority of damage to existing pipes occurs on the upper side portion thereof. In this connection, the abovementioned position adjustment is needed in order to press the rehabilitating pipe downward because the rehabilitating pipe is made of a plastic material having a specific gravity lower than the filler, and therefore unfortunately floats above the filler.
Conventionally, the position of a rehabilitating pipe is adjusted utilizing a method wherein a squared member fabricated to the required height (thickness) is interposed as a spacer in the gap between the rehabilitating pipe outer periphery and the existing pipe inner wall surface. In addition, Japanese Patent Laid Open Publication No. 2003-286742 discloses a method of adjusting the position of the rehabilitating pipe, wherein a bolt that constitutes a spacer is screwed to a block (segment) that constitutes the rehabilitating pipe so that the bolt can advance or retreat in the direction protruding from the rehabilitating pipe outer periphery and in the reverse direction thereof and is screwed to increase or decrease the length at which it protrudes from the rehabilitating pipe outer periphery.
Nevertheless, in the abovementioned method that uses a squared member as a spacer, several types of squared members must be prepared having height dimensions in accordance with the dimension of the gap between the rehabilitating pipe outer periphery and the existing pipe inner wall. In addition, in the case of the spacer comprising a bolt as mentioned above, a screw hole must be fabricated for the bolt into the block that constitutes the rehabilitating pipe, and it is moreover necessary to plug that screw hole in a downstream process. Either way, it is problematic that adjusting the position of the rehabilitating pipe requires labor, and that position adjustment cannot be performed simply and in a short time period.
An object of the present invention is therefore to provide a position adjusting spacer that can appropriately adjust the position of a rehabilitating pipe inside an existing pipe during existing pipe rehabilitating work, and also to provide a position adjusting method that utilizes such a spacer.